1. Field of the Invention
The present invention relates to an infrared light source which emits infrared by generating heat by energizing a resistor.
2. Description of the Related Art
As a heretofore known infrared light source, a structure wherein a filament which forms a resistor is provided on single crystal silicon which is a support substrate, via an insulating film, is shown. Further, the infrared light source emits infrared using heat energy generated by energizing the filament. Furthermore, an infrared light source wherein the single crystal silicon immediately below the filament is etched away using bulk microelectromechanical systems (MEMS) and a heat generation portion is formed as a heat insulation structure, thus increasing energy efficiency, is proposed (for example, refer to PTL 1).
Also, an infrared light source wherein the single crystal silicon immediately below the heat generation portion of the infrared light source is etched away using the bulk MEMS, in the same way as in PTL 1, and the heat generation portion and an electrode pad provided on the support substrate side are electrically joined via a support body which forms a beam, thereby improving heat insulation characteristics, thus enhancing heat generation efficiency, is proposed (for example, refer to PTL 2).
However, the infrared light sources in PTLs differ in emissivity according to a filament material which forms a heat generation body or to the material of the resistor. Because of this, in order to produce a stable, high heat emission in an infrared wavelength region, it has been necessary to additionally provide an emissivity stabilizing member (for example, siliconit (PTL 1)), a highly emissive film (for example, carbon black, gold, platinum, chromium, or silicon carbide (PTL 2)), or the like.
That is, the infrared light source has heretofore needed two components; a heat generation portion and an emissivity stabilizing member or a highly emissive film, thus forming two-tier structure. Because of this, complex and special manufacturing steps have been necessary to obtain a desired function and performance. Furthermore, it is necessary to provide an emissivity stabilizing member or a highly emissive film in either structure in order to provide a highly efficient infrared light source, resulting in a structure which is not suitable for a reduction in the cost of the light source.
PTL 1: JP-A-2001-221689
PTL 2: JP-A-2005-140594
For each of the infrared light sources disclosed in PTLs 1 and 2, apart from a heat generation resistor (a filament (PTL 1), polycrystalline silicon or a metal material (PTL 2)), an emissivity stabilizing member (siliconit (PTL 1)) or a highly emissive film (carbon black, gold, platinum, chromium, or silicon carbide (PTL 2)) has been necessary, as a component to enhance emissivity, in order to carry out heat emission. Because of this, the structure of the infrared light source itself becomes complicated and thus is not suitable for a reduction in cost.